Boxer disputed industry claims that proposed limits on carbon dioxide and other greenhouse gas emissions pose risks to the economy. The legislation "will create millions of new jobs and put us on the path to energy independence," she said.
The Senate was scheduled to begin considering the bill on Monday.
Boxer appealed for the Bush administration "to help us, not fight us" over the legislation, which would reduce U.S. greenhouse gas emissions by two-thirds over the next 42 years. Carbon dioxide, from burning fossil fuels, is the leading pollutant linked to climate change.
President Bush opposes legislation that would mandate greenhouse gas limits, arguing that global warming can be addressed through voluntary actions and technological innovations.
Boxer, chairwoman of the Senate Environment and Public Works Committee, noted that the bill has bipartisan support.
Still, while one of the bill's original authors is Sen. John Warner, R-Va., many Republicans oppose it. They say it would put too great of an economic burden on carbon-intensive industries such as electric utilities, which would pass on costs to consumers.